1. Field of the Invention
The present invention relates generally to chlorine containing plasma etch methods for forming patterned layers within microelectronics fabrications. More particularly, the present invention relates to chlorine containing plasma etch methods for forming with enhanced sidewall passivation and attenuated microloading effect patterned layers within microelectronics fabrications.
2. Description of the Related Art
Microelectronics fabrications are formed from microelectronics substrates over which are formed patterned microelectronics conductor layers which are separated by microelectronics dielectric layers.
As microelectronics fabrication integration levels have increased and microelectronics fabrication device and patterned microelectronics conductor layer dimensions have decreased, it has become increasingly more important to fabricate within microelectronics fabrications narrow linewidth patterned microelectronics conductor layers, such as patterned aluminum containing conductor layers, with increased aspect ratios. Within advanced microelectronics fabrications, narrow linewidth patterned microelectronics conductor layers typically desirably have a minimum linewidth of less than about 1.0 microns, more preferably from about 0.2 to about 0.5 microns, while such patterned microelectronics conductor layers typically simultaneously possess an aspect ratio of greater than about 1, more preferably from about 2 to about 3.
While narrow linewidth and high aspect ratio patterned aluminum containing conductor layers are thus desirable within the art of microelectronics fabrication, narrow linewidth and high aspect ratio patterned aluminum containing conductor layers are not formed entirely without problems within microelectronics fabrications. Of the problems encountered when forming within advanced microelectronics fabrications narrow linewidth patterned aluminum containing conductor layers while employing conventional chlorine containing plasma etch methods, particularly notable problems include: (1) limited thicknesses of patterned photoresist layers which may be employed when forming narrow linewidth patterned aluminum containing conductor layers, due to depth of focus limitations of photoexposure tools employed when forming those patterned photoresist layers; (2) patterned aluminum containing conductor layer sidewall inhomogeneity problems, such as undercutting or tapering; and (3) density related etching inhomogeneities, such as aspect ratio dependent etching effects and microloading effects.
It is thus desirable within the art of microelectronics fabrication to form within microelectronics fabrications narrow linewidth and high aspect ratio patterned aluminum containing conductor layers while employing chlorine containing plasma etch methods employing patterned photoresist layers of attenuated thickness to provide patterned aluminum containing conductor layers with uniform sidewall profiles while forming the patterned aluminum containing conductor layers with attenuated density related etching inhomogeneities such as aspect ratio dependent etching effects and microloading effects, that the present invention is generally directed. In a more general sense, the present invention is also directed towards forming within microelectronics fabrications while employing chlorine containing plasma etch methods employing patterned photoresist layers of attenuated thickness patterned chlorine containing plasma etchable layers, which need not necessarily be patterned aluminum containing conductor layers, with uniform sidewall profiles and attenuated density related etching inhomogeneities such as aspect ratio dependent etching effects and microloading effects.
Various methods have been disclosed within the art of microelectronics fabrication for forming patterned conductor layers, such as patterned aluminum containing conductor layers, with desirable properties within microelectronics fabrications.
For example, Kobayashi, in U.S. Pat. No. 5,211,804, discloses a plasma etch method for forming within a semiconductor integrated circuit microelectronics fabrication a patterned aluminum containing conductor layer with uniform sidewall profile of the patterned aluminum containing conductor layer and attenuated residue formation upon the patterned aluminum containing conductor layer. The plasma etch method employs a hard mask layer in conjunction with an etchant gas composition consisting essentially of a chlorine containing etchant gas, an oxygen containing etchant gas and a nitrogen containing etchant gas.
In addition, Kadomura, in U.S. Pat. No. 5,540,812, discloses a method for forming within an integrated circuit microelectronics fabrication a patterned aluminum containing conductor layer with attenuated corrosion of the patterned aluminum containing conductor layer, while forming the patterned aluminum containing conductor layer with attenuated consumption of a silicon oxide hard mask employed in forming the patterned aluminum containing conductor layer. In order to attenuate corrosion of the patterned aluminum containing conductor layer, there is employed a sulfur containing sidewall passivation layer upon the patterned aluminum containing conductor layer. In order to attenuate consumption of the silicon oxide hard mask layer, the silicon oxide hard mask layer is irradiated with a neutral beam, such as an argon beam.
Further, Yachi, in U.S. Pat. No. 5,578,163, discloses a method for forming within an integrated circuit microelectronics fabrication a patterned aluminum containing conductor layer without hardening a sidewall passivation polymer layer formed upon a sidewall of the patterned aluminum containing conductor layer. The method employs: (1) an activated hydrogen containing plasma at a temperature of less than about 150 degrees centigrade for removing from the sidewall passivation polymer layer chlorine residues; followed by (2) an oxygen containing plasma at a temperature of less than about 150 degrees centigrade for removing from the patterned aluminum containing conductor layer a patterned photoresist layer employed in defining the patterned aluminum containing conductor layer prior to removing the sidewall polymer passivation layer employing a wet chemical stripper solution.
Yet further, Lianjun et al., in U.S. Pat. No. 5,582,679, discloses a plasma etch method for forming a patterned aluminum containing conductor layer with attenuated undercutting or tapering within an integrated circuit microelectronics fabrication. Within the plasma etch method there is employed in conjunction with a chlorine containing etchant gas a nitrogen gas which provides a sidewall passivation layer upon the patterned aluminum containing conductor layer, thus attenuating undercutting or tapering of the patterned aluminum containing conductor layer.
Still further, Hanawa, in U.S. Pat. No. 5,614,060, discloses a plasma etch method for forming within an integrated circuit microelectronics fabrication a patterned metal layer with attenuated metal etch residues while simultaneously forming the patterned metal layer with attentuated erosion of a paterned photoresist layer employed in defining the patterned metal layer. Within the plasma etch method, the frequency and amplitude of a bias power are modulated to simultaneously provide for forming the patterned metal layer with attenuated metal etch residues while simultaneously forming the patterned metal layer with attenuated erosion of a patterned photoresist layer employed in defining the patterned metal layer.
Still yet further, Fukuda et al., in U.S. Pat. No. 5,660,681, discloses a method for forming within an integrated circuit microelectronics fabrication a patterned silicon containing material layer with attenuated particulate contamination and thus improved reliability and yield. The plasma etch method employs a first plasma comprising a chlorine or bromine containing etchant gas composition additionally comprising an oxygen containing species when forming the patterned silicon containing material layer from a corresponding blanket silicon containing material layer, where the first plasma is followed by a second plasma employing an oxygen containing etchant gas composition which oxidizes a sidewall of the patterned silicon containing material layer to form a silicon oxide sidewall coating. The silicon oxide sidewall coating may then be removed employing a hydrofluoric acid etchant.
Finally, Chen et al., in U.S. Pat. No. 5,700,740, discloses a method for forming within an integrated circuit microelectronics fabrication a patterned aluminum containing conductor layer with attenuated after corrosuion of the patterned aluminum containing conductor layer. The method employs an ammonium hydroxide rinsing of the patterned aluminum containing conductor layer to remove chlorine containing residues which contribute to after corrosion of the patterned aluminum containing conductor layer.
Desirable in the art of microelectronics fabrication are additional methods for forming within microelectronics fabrications patterned aluminum containing conductor layers while employing patterned photoresist layers of attenuated thicknesses to form the patterned aluminum containing conductor layers with uniform sidewall profile with attenuated density related etching inhomogeneities such as aspect ratio dependent etching effects and microloading effects. More generally desirable in the art of microelectronics fabrication are additional methods for forming within microelectronics fabrications patterned chlorine containing plasma etchable layers, which need not necessarily be patterned aluminum containing conductor layers, while employing patterned photoresist layers of attenuated thicknesses to form the patterned chlorine containing plasma etchable layers with uniform sidewall profile with attenuated density related etching inhomogeneities such as aspect ratio dependent etching effects and microloading effects.
It is towards the foregoing goals that the present invention is both specifically and more generally directed.